For example, JP-A-2003-229873 discloses a conventional vehicular system including multiple electronic control units (ECUs). In the configuration of JP-A-2003-229873, when a certain ECU detects a malfunction, diagnostic information on the ECU is stored in a storage medium, and the stored diagnostic information is read by using a diagnostic tool at a repair shop of the vehicle.
In view of a complicated control system in a vehicle in recent years, new configuration for identifying a malfunction is demanded.